Development of CAD System for Control System of Autonomous Underwater Vehicle

水下航行器已被广泛用于海洋测量和开发。这些车辆可以分为两类，自行式和牵引式。对于拖车来说，为了在海洋或海底的大范围调查中快速移动，需要对车身进行流线型设计。从运动控制的角度来看，拖车不需要快速响应，因为它的运动受母船的约束。另一方面，对于自行式飞行器，从流体力学的角度来看，一般采用钝体形状使其不稳定，为了实现良好的操纵性，作为一种控制系统应该是稳定的。使用多变量控制理论也有减少推进器数量的另一种可能性。因此，为了实现…，计算机辅助控制系统设计技术在平衡控制器(软件)功能方面发挥着巨大的作用更理想的控制系统性能。在CACSD中，需要一个非线性仿真器来评估所设计的控制系统。因此，对被控对象进行数学建模是必然的。特别是，我们必须通过在水箱中对车辆进行强迫振动试验来估计水动力系数。这里出现了一个关于我们在实验中应该达到的精确度的问题。也就是说，我们应该从基于鲁棒控制理论的CACSD的观点来回答是否允许水动力系数的不确定性。如果答案是否定的，将要求我们在水动力系数的估计中达到更高的精度。为了建立一种标准的控制系统设计方法，本文进行了以下几个步骤。首先建立了水下机器人运动的一般数学模型，该模型描述了水下机器人的6自由度运动和拖缆或脐带缆索的三维运动；其次，该模型具有很强的非线性，并通过计算机软件自动线性化。其次，基于现代控制理论设计了合适的控制系统。通过这些步骤，建立了水下机器人控制系统的标准设计方法。较少

Underwater vehicles have been widely used for ocean measurements and developments. The vehicles could be classified into two groups, self-propulsive and towed vehicles. In the case of towed vehicle, the body shape should be streamlined in order to move fast for wide area survey of the ocean or sea bottom. From the view point of the motion control the quick response is not required in the case of a towed vehicle because its motion is constrained by the mother ship. On the other hand, in the case of self-propulsive vehicle, the blunt shape is generally adopted to make it unstable from the viewpoint of hydrodynamics, and it is supposed to be stabilized in order to realize good maneuverability as a control system. There is also another possibility to reduce a number of thrusters using multivariable control theory. Therefore, CACSD (Computer-Aided Control System Design) technology is expexted to play'a great role in balancing between function of controller (software), in order to achieve th … More e desired performance of the control system. In CACSD,a nonlinear simulator is necessary to evaluate the control system designed. So it is inevitable to model the controlled object mathematically. In particular, we must estimate hydrodynamic coefficients by carrying out forced oscillating tests on the vehicle in a water tank. Here a problem occurs on the accuracy we should achieve in the experiment. That is, we should answer whether or not the uncertainties of hydrodynamic coefficients could be allowed from the viewpoint of CACSD based on robust control theory. If the answer is "no" , we will be required achieve higher accuracy in the estimation of hydrodynamic coefficients.The present research has been carried out in order to establish a standard design method of the control system as following steps. At first general mathematical models for the motions of the underwater vehicle have been constructed, which describes 6-degree freedom motions of vehicles and 3-dimensional motions of a towing cable or umbilical cable.Secondly the model has strong non-linearity and it is linearized automatically by using computer software. Next adequate control systems are designed based on modem control theory. Through these procedure a standard design method for the control system of an underwater vehicle has been established. Less